® RT8010C 1.5MHz, 1A, High Efficiency PWM Step-Down DC/DC Converter General Description Features 2.5V to 5.5V Input Voltage Range Output Voltage (Adjustable Output From 0.6V to VIN) 1A Output Current Up to 95% Efficiency No Schottky Diode Required 1.5MHz Fixed Switching Frequency Current Limit Input UVLO Protection Thermal Shutdown Small 6-Lead WDFN Package RoHS Compliant and Halogen Free The RT8010C is a high efficiency Pulse-Width-Modulated (PWM) step-down DC/DC converter, and is capable of delivering 1A output current over a wide input voltage range from 2.5V to 5.5V. The RT8010C is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources such as cellular phones, PDAs and hand-held devices. Two operating modes are available including : PWM/LowDropout autoswitch and shutdown modes. The Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical application. Applications The RT8010C enters Low Dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper P-MOSFET. RT8010C enters shut-down mode and consumes less than 0.1μA when the EN pin is pulled low. Mobile Phones Personal Information Appliances Wireless and DSL Modems MP3 Players Portable Instruments The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operating frequency of 1.5MHz. Small WDFN-6L 2x2 package provides small PCB area application. Other features include soft start, lower internal reference voltage with 2% accuracy, over temperature protection, and over current protection. Ordering Information RT8010C Package Type QW : WDFN-6L 2x2 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) Note : Marking Information Richtek products are : 1E : Product Code 1EW ` W : Date Code RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ` Suitable for use in SnPb or Pb-free soldering processes. Simplified Application Circuit L VIN VIN CIN LX RT8010C EN VOUT COUT VOUT GND Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS8010C-00 September 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8010C Pin Configurations NC 1 EN VIN 2 GND (TOP VIEW) 3 7 6 FB/VOUT 5 GND LX 4 WDFN-6L 2x2 Functional Pin Description Pin No. Pin Name Pin Function 1 NC No Internal Connection. Leave floating or connect to ground. 2 EN Chip Enable (Active High). 3 VIN Power Input. 4 LX 5, GND 7 (Exposed Pad) 6 FB/VOUT Switch Node. Connect this pin to the external inductor. Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Feedback/Output Voltage Sense Input. Function Block Diagram EN VIN RS1 OSC & Shutdown Control Current Limit Detector Slope Compensation Current Sense FB/VOUT Error Amplifier PWM Comparator UVLO & Power Good Detector Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 Control Logic Driver LX RS2 GND VREF is a registered trademark of Richtek Technology Corporation. DS8010C-00 September 2012 RT8010C Operation The RT8010C is a synchronous step-down DC/DC converter with two integrated power MOSFETs and operates at 1.5MHz fixed frequency. Daring normal operation, the internal high side power switch (P-MOSFET) is turned on at the beginning of each clock cycle. Current in the inductor increases until the peak inductor current reaches the value defined by the output voltage of the error amplifier. The error amplifier adjusts its output voltage by comparing the feedback signal on the FB pin with an internal 0.6V reference. When the load current increases, it causes a drop in the feedback voltage relative to the reference, and the COMP voltage will rise to allow higher inductor current to match the load current. OSC Over Temperature Protection (OTP) The RT8010C implement an internal over temperature protection. When junction temperature is higher than 160°C, it will stop switching. Once the junction temperature cools down, the RT8010C will automatically resume switching. Enable Comparator A logic-high enable the converter, a logic-low forces the IC into shutdown mode. Soft-Start (SS) An internal current source charges an internal capacitor to build the soft-start ramp voltage. The FB voltage will track the internal ramp voltage during the soft-start interval. The internal oscillator typically runs at 1.5 MHz switching frequency. Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS8010C-00 September 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT8010C Absolute Maximum Ratings (Note 1) Supply Input Voltage, VIN ----------------------------------------------------------------------------------------EN, FB Pin Voltage ------------------------------------------------------------------------------------------------LX Pin Switch Voltage ---------------------------------------------------------------------------------------------<20ns -----------------------------------------------------------------------------------------------------------------LX Pin Switch Current ---------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C WDFN-6L 2x2 -------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) WDFN-6L 2x2, θJA --------------------------------------------------------------------------------------------------WDFN-6L 2x2, θJC -------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Model) ---------------------------------------------------------------------------------------- Recommended Operating Conditions 6.5V −0.3V to VIN −0.3V to (VIN + 0.3V) −4.5V to 7.5V 2A 0.833W 120°C/W 8°C/W 260°C −65°C to 150°C 150°C 2kV (Note 4) Supply Input Voltage ------------------------------------------------------------------------------------------------ 2.5V to 5.5V Junction Temperature Range -------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = 3.6V, VOUT = 2.5V, L = 2.2μH, CIN = 4.7μF, COUT = 10μF, TA = 25°C, IMAX = 1A unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit 2.5 -- 5.5 V Input Voltage Range VIN Quiescent Current IQ IOUT = 0mA, VFB = VREF + 5% -- 50 70 μA Shutdown Current ISHDN EN = GND -- 1 10 μA Reference Voltage VREF For Adjustable Output Voltage 0.588 0.6 0.612 V Adjustable Output Range VOUT (Note 5) VREF -- VIN − 0.2V V Output Voltage Accuracy ΔVOUT VIN = VOUT + ΔV to 5.5V 0A < IOUT < 1A −3 -- 3 % FB Input Current IFB VFB = VIN −50 -- 50 nA 0.28 -- RDS(ON)_P IOUT = 200mA VIN = 3.6V -- P-MOSFET RON VIN = 2.5V -- 0.38 -- 0.25 -- RDS(ON)_N IOUT = 200mA VIN = 3.6V -- N-MOSFET RON VIN = 2.5V -- 0.35 -- P-Channel Current Limit ILIM_P VIN = 2.5V to 5.5V 1.4 1.5 -- Logic-High VEN_H VIN = 2.5V to 5.5V 1.5 -- VIN Logic-Low VEN_L VIN = 2.5V to 5.5V -- -- 0.4 EN Input Voltage Adjustable Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 (Note 6) Ω Ω A V is a registered trademark of Richtek Technology Corporation. DS8010C-00 September 2012 RT8010C Parameter Symbol Min Typ Max Unit Under Voltage Lockout Threshold UVLO -- 1.8 -- V UVLO Hysteresis -- 0.1 -- V 1.2 1.5 1.8 MHz -- 160 -- °C 100 -- -- % −1 -- 1 μA Oscillator Frequency fOSC Thermal Shutdown Temperature TSD Test Conditions VIN = 3.6V, IOUT = 100mA Maximum Duty Cycle LX Leakage Current VIN = 3.6V, VLX = 0V or VLX = 3.6V Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package. Note 3. Devices are ESD sensitive. Handling precaution recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. Guarantee by design. Note 6. ΔV = IOUT x PRDS(ON) Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS8010C-00 September 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT8010C Typical Application Circuit VIN 2.5V to 5.5V 3 CIN 4.7µF LX VIN 4 L 2.2µH VOUT COUT 10µF RT8010C 2 EN VOUT 6 GND 5 Figure 1. Fixed Output Voltage VIN 2.5V to 5.5V 3 CIN 4.7µF L 2.2µH VIN LX EN FB GND 5 ⎛ ⎝ VOUT C1 RT8010C 2 VOUT = VREF × ⎜ 1 + 4 R1 COUT 10µF 6 IR2 R2 R1 ⎞ ⎟ R2 ⎠ with R2 = 300kΩ to 60kΩ so the IR2 = 2μA to 10μA, and (R1 x C1) should be in the range between 3x10−6 and 6x10−6 for component selection. Figure 2. Adjustable Output Voltage Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS8010C-00 September 2012 RT8010C Typical Operating Characteristics Efficiency vs. Output Current Efficiency vs. Output Current 100 100 90 80 80 70 Efficiency (%) Efficiency (%) 90 VIN = 3.6V VIN = 4.2V VIN = 5V 60 50 40 30 70 VIN = 5V VIN = 3.3V VIN = 2.5V 60 50 40 30 20 20 10 10 VOUT = 3.3V, COUT = 4.7μF, L = 4.7μH VOUT = 1.2V, COUT = 4.7μF, L = 4.7μH 0 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 1 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Output Current (A) Output Current (A) Efficiency vs. Output Current UVLO Voltage vs. Temperature 100 2.0 90 1.9 Rising 70 Input Voltage (V) Efficiency (%) 80 VIN = 5V VIN = 3.3V VIN = 2.5V 60 50 40 30 1.8 1.7 1.6 Falling 1.5 1.4 20 1.3 10 VOUT = 1.2V, IOUT = 0A VOUT = 1.2V, COUT = 10μF, L = 2.2μH 0 1.2 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 -40 -25 -10 5 1.5 1.5 1.4 1.4 EN Pin Threshold (V) EN Pin Threshold (V) 1.6 1.3 1.2 1.1 Rising 0.9 0.8 35 50 65 80 95 110 125 EN Pin Threshold vs. Temperature EN Pin Threshold vs. Input Voltage 1.6 1.0 20 Temperature (°C) Output Current (A) Falling 0.7 1.3 1.2 1.1 1.0 Rising 0.9 0.8 Falling 0.7 0.6 0.6 0.5 VOUT = 1.2V, IOUT = 0A 0.5 VIN = 3.6V, VOUT = 1.2V, IOUT = 0A 0.4 0.4 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 Input Voltage (V) Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS8010C-00 September 2012 5.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT8010C Output Voltage vs. Temperature 1.25 1.24 1.24 1.23 1.23 1.22 Output Voltage (V) Output Voltage (V) Output Voltage vs. Load Current 1.25 VIN = 5V 1.21 VIN = 3.6V 1.20 1.19 1.18 1.22 1.21 1.20 1.19 1.18 1.17 1.17 1.16 1.16 1.15 1.15 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 VIN = 3.6V, IOUT = 0A -40 -25 -10 5 35 50 65 80 95 110 125 Frequency vs. Temperature 1.60 1.60 1.55 1.55 1.50 1.50 Frequency (kHz)1 Frequency (kHz) Frequency vs. Input Voltage 1.45 1.40 1.35 1.30 1.45 1.40 1.35 1.30 1.25 1.25 VIN = 3.6V, VOUT = 1.2V, IOUT = 300mA VIN = 3.6V, VOUT = 1.2V, IOUT = 300mA 1.20 1.20 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 -40 -25 -10 5.5 5 Output Current Limit vs. Input Voltage 35 50 65 80 95 110 125 Output Current Limit vs. Temperature 2.6 2.5 2.5 2.4 2.4 Output Current Limit (A) 2.6 2.3 2.2 2.1 2.0 1.9 1.8 1.7 1.6 20 Temperature (°C) Input Voltage (V) Output Current Limit (A) 20 Temperature (°C) Load Current (A) VOUT = 1.2V @ TA = 20°C 1.5 2.3 VIN = 5V VIN = 3.6V 2.2 2.1 VIN = 3.3V 2.0 1.9 1.8 1.7 1.6 VOUT = 1.2V 1.5 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 Input Voltage (V) Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 5.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. DS8010C-00 September 2012 RT8010C Power On from EN Power On from EN VIN = 3.6V, VOUT = 1.2V, IOUT = 10mA VIN = 3.6V, VOUT = 1.2V, IOUT = 1A VEN (2V/Div) VEN (2V/Div) VOUT (1V/Div) VOUT (1V/Div) I IN (500mA/Div) I IN (500mA/Div) Time (100μs/Div) Time (100μs/Div) Load Transient Response Load Transient Response VIN = 3.6V, VOUT = 1.2V IOUT = 50mA to 0.5A VIN = 3.6V, VOUT = 1.2V IOUT = 50mA to 1A VOUT ac (50mV/Div) VOUT ac (50mV/Div) IOUT (500mA/Div) IOUT (500mA/Div) Time (50μs/Div) Time (50μs/Div) Load Transient Response Load Transient Response VIN = 5V, VOUT = 1.2V IOUT = 50mA to 0.5A VIN = 5V, VOUT = 1.2V IOUT = 50mA to 1A VOUT ac (50mV/Div) VOUT ac (50mV/Div) IOUT (500mA/Div) IOUT (500mA/Div) Time (50μs/Div) Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS8010C-00 September 2012 Time (50μs/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT8010C Output Ripple Voltage Output Ripple Voltage VIN = 3.6V, VOUT = 1.2V IOUT = 1A VIN = 5V, VOUT = 1.2V IOUT = 1A VOUT (10mV/Div) VOUT (10mV/Div) VLX (2V/Div) VLX (2V/Div) Time (500ns/Div) Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 Time (500ns/Div) is a registered trademark of Richtek Technology Corporation. DS8010C-00 September 2012 RT8010C Applications Information The basic RT8010C application circuit is shown in Typical Application Circuit. External component selection is determined by the maximum load current and begins with the selection of the inductor value and operating frequency followed by CIN and COUT. Inductor Selection For a given input and output voltage, the inductor value and operating frequency determine the ripple current. The ripple current ΔIL increases with higher VIN and decreases with higher inductance. V V ΔIL = ⎡⎢ OUT ⎤⎥ × ⎡⎢1− OUT ⎤⎥ VIN ⎦ ⎣ f ×L ⎦ ⎣ Having a lower ripple current reduces the ESR losses in the output capacitors and the output voltage ripple. Highest efficiency operation is achieved at low frequency with small ripple current. This, however, requires a large inductor. A reasonable starting point for selecting the ripple current is ΔIL = 0.4(IMAX). The largest ripple current occurs at the highest VIN. To guarantee that the ripple current stays below a specified maximum, the inductor value should be chosen according to the following equation : ⎡ VOUT ⎤ ⎡ VOUT ⎤ L= ⎢ ⎥ × ⎢1 − VIN(MAX) ⎥ f I × Δ L(MAX) ⎣ ⎦ ⎣ ⎦ Using Ceramic Input and Output Capacitors Higher values, lower cost ceramic capacitors are now becoming available in smaller case sizes. Their high ripple current, high voltage rating and low ESR make them ideal for switching regulator applications. However, care must be taken when these capacitors are used at the input and output. When a ceramic capacitor is used at the input and the power is supplied by a wall adapter through long wires, a load step at the output can induce ringing at the input, VIN. The ringing can couple with the output and be mistaken as loop instability. At worst, a sudden inrush of current through the long wires can potentially cause a voltage spike at VIN large enough to damage the part. Output Voltage Setting The resistive divider allows the FB pin to sense a fraction of the output voltage as shown in Figure 3. Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS8010C-00 September 2012 VOUT R1 FB RT8010C R2 GND Figure 3. Setting the Output Voltage For adjustable voltage mode, the output voltage is set by an external resistive divider according to the following equation : VOUT = VREF ⎛⎜ 1+ R1 ⎞⎟ ⎝ R2 ⎠ where VREF is the internal reference voltage (0.6V typ.) Thermal Considerations The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The maximum power dissipation can be calculated by following formula : PD(MAX) = (TJ(MAX) − TA) / θJA Where T J(MAX) is the maximum operation junction temperature, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT8010C DC/DC converter, where TJ(MAX) is the maximum junction temperature of the die and TA is the maximum ambient temperature. The junction to ambient thermal resistance θJA is layout dependent. For WDFN-6L 2x2 package, the thermal resistance θJA is 120°C/W on the standard JEDEC 51-7 four layers thermal test board. The maximum power dissipation at TA = 25°C can be calculated by following formula : PD(MAX) = (125°C − 25°C) / 120°C/W = 0.833W for WDFN-6L 2x2 package The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. The derating curve in Figure 4 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT8010C Maximum Power Dissipation (W) 1.6 Four-Layers PCB VIN 1.4 1.2 C2 1 1.0 NC C1 2 EN R1 6 FB/VOUT 0.8 VOUT L1 RT8010C 3 4 VIN LX C3 5 GND R2 0.6 VIN 0.4 0.2 R3 0.0 0 25 50 75 100 125 Figure 5. EVB Schematic Ambient Temperature (°C) Figure 4. Derating Curve of Maximum Power Dissipation Checking Transient Response The regulator loop response can be checked by looking at the load transient response. Switching regulators take several cycles to respond to a step in load current. When a load step occurs, VOUT immediately shifts by an amount equal to ΔILOAD (ESR), where ESR is the effective series resistance of COUT. ΔILOAD also begins to charge or discharge COUT generating a feedback error signal used by the regulator to return VOUT to its steady-state value. During this recovery time, VOUT can be monitored for overshoot or ringing that would indicate a stability problem. RT8010C_FIX NC 1 6 VOUT EN 2 5 GND VIN 3 4 LX L1 COUT CIN LX should be connected to Inductor by wide and short trace, keep sensitive components away from this trace CIN must be placed to the VIN as close as possible. Place the feedback components close to the FB pin. Layout Considerations Follow the PCB layout guidelines for optimal performance of RT8010C. ` ` ` ` ` For the main current paths as indicated in bold lines in Figure 5, keep these traces short and wide. Put the input capacitor as close as possible to the device pins (VIN and GND). LX node is with high frequency voltage swing and should be kept within small area. Keep analog components away from LX node to prevent stray capacitive noise pick-up. Connect feedback network behind the output capacitors. Keep the loop area small. Place the feedback components near the RT8010C. Output capacitor must be near RT8010 RT8010C_ADJ R2 NC 1 6 FB EN 2 5 GND VIN 3 4 LX R1 L1 COUT CIN CIN must be placed to the VIN as close as possible. LX should be connected to Inductor by wide and short trace, keep sensitive components away from this trace Figure 6. PCB Layout Guide An example of 2-layer PCB layout is shown in Figure 6 for reference. Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS8010C-00 September 2012 RT8010C Table 1. Recommended Inductors Supplier Inductance (μH) Current Rating (mA) DCR (mΩ) Dimensions (mm) Series TAIYO YUDEN 2.2 1480 60 3.00 x 3.00 x 1.50 NR 3015 GOTREND 2.2 1500 58 3.85 x 3.85 x 1.80 GTSD32 Sumida 2.2 1500 75 4.50 x 3.20 x 1.55 CDRH2D14 Sumida 4.7 1000 135 4.50 x 3.20 x 1.55 CDRH2D14 TAIYO YUDEN 4.7 1020 120 3.00 x 3.00 x 1.50 NR 3015 GOTREND 4.7 1100 146 3.85 x 3.85 x 1.80 GTSD32 Table 2. Recommended Capacitors for CIN and COUT Supplier Capacitance (μF) Package Part Number TDK 4.7 0603 C1608JB0J475M MURATA 4.7 0603 GRM188R60J475KE19 TAIYO YUDEN 4.7 0603 JMK107BJ475RA TAIYO YUDEN 10 0603 JMK107BJ106MA TDK 10 0805 C2012JB0J106M MURATA 10 0805 GRM219R60J106ME19 MURATA 10 0805 GRM219R60J106KE19 TAIYO YUDEN 10 0805 JMK212BJ106RD Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS8010C-00 September 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT8010C Outline Dimension D2 D L E E2 1 e b A A1 SEE DETAIL A 2 1 2 1 A3 DETAIL A Pin #1 ID and Tie Bar Mark Options Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.200 0.350 0.008 0.014 D 1.950 2.050 0.077 0.081 D2 1.000 1.450 0.039 0.057 E 1.950 2.050 0.077 0.081 E2 0.500 0.850 0.020 0.033 e L 0.650 0.300 0.026 0.400 0.012 0.016 W-Type 6L DFN 2x2 Package Richtek Technology Corporation 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries. www.richtek.com 14 DS8010C-00 September 2012